There is evidence that during hypotension and shock there is excessive and continuous impulse traffic in efferent nerves of spleen, kidney and limb, even after normal blood volume is restored. This suggests that hypotension and its concomitant, hypoxia, may interfere with the central programming of the pattern and sequence of moderatory reflexes to such an extent that cardiovascular equilibrium between central and peripheral functions compatible with life cannot be achieved. Toxemia could act in a similar fachion. The hypothesis is advanced that disruption of the delicate central mechanism for fine co-ordination of heart rate, myocardial contractility, arteriolar territorial resistances, blood reservoir capacity and body water distribution will initiate or perpetuate shock. Such disruption would be made evident by abnormal intensity and patterns of efferent nerve impulse activity. The aim of this research is to examine the intensity and pattern of autonomic nervous system activity in an organ composed primarily of vascular-like smooth muscle (dog spleen) before during and after the production of irreversible shock. Later the investigation will be extended to the efferent innervation of kidney and limbs. With luck, some way may be found to modify the intensity, pattern or sequence of nerve activity which will either prevent, delay or abolish shock